◆ Platform Introduction
Transdermal administration is a special route of drug delivery that exerts local or systemic therapeutic effects by contacting the skin and acting directly or permeating through it. Due to clinical advantages such as bypassing hepatic first-pass metabolism, reducing gastrointestinal degradation and inactivation, lowering gastrointestinal side effects, prolonging drug action duration, reducing dosing frequency, and maintaining constant blood drug concentration, transdermal preparations have become the third major route of administration after oral and injection.
LEWWIN PHARM has successfully established an internationally leading transdermal preparation research platform, capable of providing non-clinical pharmacology and pharmacodynamic, pharmacokinetic, and safety evaluation services for transdermal preparations that comply with domestic and international regulations. Transdermal dosage forms that have been studied include but are not limited to: patches, ointments, gels, powders, transdermal preparations, microneedles, lotions, cataplasms, sprays, tinctures, etc.
◆ Safety Evaluation Studies
● Single-dose dermal toxicity on intact and abraded skin (including juvenile animals): Rat, Rabbit, Minipig
● Repeat-dose dermal toxicity on intact and abraded skin (including juvenile animals): Rat, Rabbit, Minipig
● Single-dose dermal toxicity on deep second-degree burn skin: Rabbit, Minipig
● Repeat-dose dermal toxicity on deep second-degree burn skin: Rabbit, Minipig
● Single-dose dermal irritation on intact and abraded skin: Rabbit, Minipig
● Repeat-dose dermal irritation on intact and abraded skin: Rabbit, Minipig
● Dermal phototoxicity: Guinea pig
● Active Cutaneous Anaphylaxis (ACA): Guinea pig
● Buehler Test (BT): Guinea pig
● Skin photoallergy reaction: Guinea pig
◆ Animal Models for Skin Diseases
Pressure Ulcer Model
A self-made pressure device (with good repeatability, simple and safe experimental operation and device) simulates pressure ulcer (decubitus ulcer) wounds of varying degrees in skin tissue by controlling pressure and time on a specific pressure area, forming pressure ulcers at different stages. It investigates wound healing and contraction rate, partially simulating the clinical characteristics of pressure ulcer occurrence.
Pressure Ulcer Modeling and Manifestations
Guinea Pig Skin Herpes Simplex Virus (HSV-1) Model
Guinea Pig Herpes Simplex Vaginitis (HSV-2) Model
◆ PK Studies for Transdermal Preparations
● Systemic Exposure PK Study: Measures exposure in the blood.
● Local Skin Exposure PK Study: Divides skin tissue into the epidermal layer, dermal layer, subcutaneous tissue, and underlying muscle, and measures drug exposure in each layer separately.
Case: PK of a Transdermal Drug for Treating Skin Cancer
